Look up parthenogenesis it can happen(however I doubt you have much to worry about) has been documented in a few species as far as I'm aware, females can also retain sperm for years after pairing with a male.
I don't believe all offspring are female I've seen articles on American yellow belly water snakes and boas that have produced offspring via parthenogenesis. The offspring were tested and were genetically identical to mother.
It can also happen among komodo dragons and correct me if I'm wrong, I believe it can happen with bearded dragons.
Heres a link if your interested in this matter. http://www.abc.net.au/catalyst/stories/4353577.htm
(Please take this down if not allowed)
-Kind regards Sam
It has happened with other species of pythons too, and many other reptiles, although it's extremely unlikely to happen with any of your pet Australian pythons.
There are many different ways parthenogenesis can work. In most of the stick insects, all offspring are clonal, female copies of the mother. In all obligate parthenogens (the ones which only reproduce by parthenogenesis and are incapable of sexual reproduction) that's the case too. In some cases the offspring are all male, familiar examples include turkeys (yes, it's rare but it happens in turkeys) and snake mites. In both of these, sexually produced offspring can be female, but parthenogenetically produced offspring are all male (and fertile). They tried experimenting by breeding the male turkeys produced parthenogenetically, and obtaining parthenogenetically produced males from their daughters, and so on, and the rate of parthenogenesis increased each generation. Pretty interesting stuff.
In some cases, including some, maybe most of the pythons, the offspring are not clones of the mother, even if they are female. If you don't know much about genetics it's difficult to explain, but it's a little like selfing in plants, like the ultimate form of inbreeding.
I could blabber on all day about parthenogenesis, but the short story is that it's unlikely enough that you can consider it to be impossible in your case.